CN107315230A - Metallized optical fibre - Google Patents

Abstract

A metallized optical fiber comprising: A) an optical fiber, and B) a conductive metal surrounding and in contact with the optical fiber, the conductive metal having a thickness of at least 0.15 times the thickness of the optical fiber. Metallized optical fibers can form hybrid fiber/coaxial cable components that provide good protection for data signals propagating along the fiber from electrical currents from adjacent or nearby electrical conductors.

Description

metallized optical fiber

The application of the present invention is based on the divisional application of the patent application with the filing date of September 5, 2013, the application number of 201380061311.2 (the international application number is PCT/US2013/058182), and the title of the invention is "metallized optical fiber".

technical field

The present invention relates to optical fibers. In one aspect, the present invention relates to optical fibers comprising metallized strips or coatings, and in another aspect, the present invention relates to metallized optical fibers as part of a hybrid optical fiber/coaxial cable.

Background technique

Hybrid fiber/coax cables that combine fiber optic and coaxial cables have been commonly used by cable television operators worldwide since the early 1990s. There are many applications that require both power and data transmission. For example, in a smart home, there are advanced automation systems for lighting, temperature control, multimedia, security equipment, window and door operation, and many other functions. This smart function is accomplished by sending coded signals through the home wiring to switches and outlets that are programmed to operate electrical and electronic devices in every part of the home. Signaling includes both power and data signals.

Another example is a tower top radio (TTR) cell phone tower. The TTR is connected to common equipment via a small diameter cable consisting of glass or plastic fibers carrying digital signals and a pair of copper wires supplying power. In applications requiring both power and data transmission, hybrid cables are required. However, many consumer applications require wiring or cables that are smaller in size and lighter in weight, so that the power and data carrying components of hybrid cables are always brought closer together. This in turn can lead to problems with power signals interfering with data signals, or vice versa. Therefore, there is a need for a hybrid cable that can contain power and data conductors that are close to each other without interfering with each other's functionality.

Contents of the invention

In one embodiment, the invention is a metallized optical fiber comprising:

A) optical fiber, and

B) Conductive metal surrounding and in contact with the optical fiber, the thickness of the conductive metal being at least 0.15 times the thickness of the optical fiber.

In one embodiment, the invention is a hybrid fiber optic/coaxial cable comprising:

A) coaxial cable, and

B) Metallized optical fiber comprising:

1) optical fiber; and

2) Conductive metal, the conductive metal surrounds the optical fiber and is in contact with the optical fiber, the thickness of the conductive metal

At least 0.15 times the thickness of the optical fiber.

In one embodiment, the invention is a metallized fiber optic or hybrid fiber/coaxial cable, both of which are connected to a power source as described above.

In one embodiment, the invention is a method of transmitting a data signal through a metallized optical fiber, said method comprising the step of transmitting a data signal through a metallized optical fiber comprising the optical fiber and a metal coating surrounding and in contact with the optical fiber, The thickness of the metal coating is greater than the wavelength of the data signal.

Description of drawings

Figure 1 is a schematic diagram of a metallized optical fiber.

FIG. 2 is a schematic diagram of a prior art hybrid fiber/coaxial cable.

Figure 3 is a schematic diagram of one embodiment of the hybrid fiber/coaxial cable of the present invention.

detailed description

definition

Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percentages are by weight. For purposes of U.S. patent practice, the contents of any referenced patent, patent application, or publication are hereby incorporated by reference in their entirety (or their equivalent U.S. equivalents), particularly with respect to synthetic techniques, definitions ( not inconsistent with any definition specifically provided in this application) and common sense disclosure.

Numerical ranges in this application are approximations and therefore may include values outside the range unless otherwise indicated. Numerical ranges include all values from the lower value to the upper value, in increments of 1 unit, provided that there is a separation of at least 2 units between any lower value and any higher value. For example, if compositional, physical or other properties, such as molecular weight, viscosity, melt index, etc., are from 100 to 1,000, it is meant that all individual values are explicitly recited, such as 100, 101, 102, etc., and all subranges, such as 100 to 144, 155 to 170, 197 to 200, etc. For ranges containing numbers which are less than one or containing fractional numbers greater than one (eg 1.1, 1.5 etc.), 1 unit is considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate. For ranges containing single digit numbers less than ten (eg, 1 to 5), 1 unit is typically considered to be 0.1. These are merely examples of what is specifically intended and all possible combinations of values between the lowest and highest values enumerated are considered to be expressly recited in this application. The numerical ranges within this application provide, inter alia, the thickness of the metal coating around the fiber optic cable.

"Comprising", "comprising", "having" and their derivatives are not intended to exclude the presence of any additional elements, steps or procedures, regardless of whether the same content is specifically disclosed. In order to remove any doubt, using the term "comprising" all compositions claimed may include any additional additive, adjuvant or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term "consisting essentially of" excludes from the scope of any subsequent recitation any other parts, steps or procedures, except those parts, steps or procedures that are not necessary for the operation. The term "consisting of" excludes any component, step or procedure not specifically recited or enumerated.

"Cable", "cable" and like terms mean at least one wire or optical fiber within a protective jacket or sheath. Typically, a cable is two or more wires or optical fibers bundled together, typically in the same protective jacket or sheath. The individual wires or fibers inside the jacket can be bare, sheathed or insulated. Hybrid or combination cables may contain both electrical wires and optical fibers. Cables and more can be designed for low, medium and high voltage applications. Typical cable designs are described in USP 5,246,783, 6,496,629 and 6,714,707.

"Optical fiber" and like terms mean a fiber consisting of a core and cladding selected for total internal reflection due to the difference in refractive index between the two. The cladding is typically coated with an acrylate polymer or polyimide layer. The coating protects the fiber from damage but does not contribute to its light wavelength properties.

The terms "coaxial cable", "coaxial cable" and like terms mean a cable comprising an inner conductor surrounded by a flexible, tubular insulation, surrounded by a tubular conductive shield. The term "coaxial" means that the inner conductor and outer shield share a geometric axis.

metallized optical fiber

In one embodiment, the invention is a metallized optical fiber. One design is shown in Figure 1. Metallized optical fiber 10 includes optical fiber 11 and metal strip 12 . Optical fiber 11 has a generally cylindrical configuration, although its configuration can vary as desired. The composition of the core (e.g., glass or plastic; not shown) and the number, thickness, and composition of the cladding layer(s) (e.g., acrylate, imide, etc.; not shown) can also be determined according to Change is needed. These and other considerations regarding optical fiber composition and construction, and methods of their construction, are well known in the art.

The metal strip 11 is in contact with the optical fiber 10 . The metal strip 11 may comprise any conductive metal, such as copper, aluminum, platinum group metals (platinum, palladium, etc.), noble metals (eg, gold, silver), etc., and the size, configuration, and thickness of the metal strip 11 may vary. Copper is the preferred metal for use in the present invention. In one embodiment, the metal strip completely, or nearly completely (eg, less than 100% but greater than 90%, or greater than 95%, or greater than 99%) covers the entire surface of the optical fiber. In one embodiment, the metal strip covers less than the entire surface of the fiber, in such an embodiment the metal strip covers at least 89%, preferably at least 50%, more preferably at least 20% and even more preferably at least 10% of the fiber surface. If the metal strip covers less than the entire surface area of the optical fiber, the configuration of the metal strip can be changed according to needs, such as straight line, zigzag, serpentine, spiral, etc., and the metal strip extends along the longitudinal axis of the optical fiber.

The thickness of the metal strip is greater than the transmitted signal frequency. For an optical fiber designed to carry 60 hertz (Hz) frequency signals, the metal (eg, copper) thickness is typically about 8.5 millimeters (mm). As long as the thickness of the metal strip is greater than the frequency of the signal carried by the fiber, the transmitted signal is the same as through a metal rod with the same surface area. Due to the thickness of the metal, the power signal will travel on the metal strip without passing through the fiber itself, so the power signal will not interfere, or only at a nominal level, with the data signal carried by the fiber. Metal thickness calculations for any given signal frequency are known in the art, as exemplified in: Electrical Losses in Coaxial Cable by Eaton and Kmiec, International Wire & Cable Symposium , Proceedings of the 57 ^th IWCS, pp.515 -520 (Nov 2008).

The skin effect of a conductor is the tendency of the current itself to distribute within the conductor such that the density of the current near the surface of the conductor is greater than the current density at the core of the conductor. The skin depth δ is inversely proportional to the square of the frequency:

δ(m)=sqrt((2*ρ)/*ω*μ))

where ρ is the resistivity of the conductor, ω is the angular frequency of the current = 2π, and μ is the absolute permeability of the conductor. For copper conductors, the equation is summarized as follows:

δ(m)＝0.06/sqrt(frequency(Hz)).

At 60 Hz, the skin depth was 8.5 mm; at 1 MHz, the skin depth was 66 μm; and at 1 GHz, the skin depth was 2.08 μm.

In one embodiment of the invention, the thickness of the metal on the fiber is a function of the dimension of the fiber, eg thickness or diameter. Typically, the metal thickness is at least 0.15, more typically at least 1, and even more typically at least 2 times the thickness or diameter of the optical fiber. Thus, if the fiber has a thickness or diameter of 1 mm, the thickness of the metal in contact with the fiber is at least 0.15 mm, preferably at least 1 mm and even more preferably at least 2 mm.

The metal can be applied to the optical fiber in any convenient manner, such as by electroplating, electrolytic plating, use of adhesives (see, eg, USSN 61/577918 filed December 20, 2011), and the like. These methods are known in the art and can be used in combination with each other, for example, applying a thin (e.g., 1-100 micron) initial layer to the fiber surface, followed by electroplating one or more layers on top of the initial layer to make up the total thickness 1,000 microns, 1,500 microns or larger. While electroplating and electrolytic plating are well suited for coating the entire surface of an optical fiber, these techniques are also used to coat less than the entire surface of an optical fiber by utilizing various known masking and rinsing techniques. If an adhesive is used, it typically has good dielectric properties and exhibits good bond strength to the metal and the composition of the optical fiber's outermost cladding (eg, acrylic). Hybrid Fiber/Coax

Hybrid cables include, but are not limited to, fiber optic cables, coaxial cables, and electrical conductors such as copper. These hybrid cables carry both data and power. In the hybrid cable of the present invention, electrical conductors such as copper may be replaced by optical fibers coated with current-carrying metal strips. Fiber optic cables can carry more data (higher bandwidth) with less noise and less susceptibility to interference than coaxial cables.

In one embodiment, the invention is a hybrid fiber/coaxial cable. Figure 2 illustrates one embodiment of a prior art design for a hybrid fiber coaxial cable. Hybrid fiber/coaxial cable 20 includes a central core strength member 21 designed to impart load bearing strength to the hybrid cable. This member of the hybrid cable is typically made of metal or high strength plastic, the member does not carry power or information. Electrical conductors 22, 23 and 25, typically made of copper or aluminum, carry electricity, ie current. These conductors are typically embedded in one or more semiconductor and/or insulating sheaths (not shown). Cable 24 is a coaxial cable.

Fiber optic cable 26 contains four optical fibers embedded in a protective jacket. Each fiber may itself be embedded in one or more protective sheaths, and the space between the four fibers may be filled with a matrix filler that provides both protection and dielectric insulation.

The strength members and various conductors of the hybrid cable are embedded in a filler matrix 27 which provides both protection from physical damage and dielectric insulation. This matrix is then embedded within a semiconductive insulating sheath 28 which in turn is embedded within an outer protective jacket 29 . Various compositions of matrix packings, semiconducting jackets and protective jackets and various methods of making matrix packings, semiconducting jackets and protective jackets are well known in the art.

One embodiment of the hybrid cable of the present invention is depicted in FIG. 3 . Hybrid cable 30 is similar in design to hybrid cable 20 except that hybrid cable 30 does not contain stand-alone electrical conductors 22 , 23 and 25 . Instead, the fiber optic cable 26 is replaced by a fiber optic cable 36 in which the four optical fibers are metallized, ie they contain a metal coating, one embodiment of which is depicted in FIG. 1 . This metal strip or coating performs the function of one or more electrical conductors of the prior art hybrid cable described in FIG. 2 .

The hybrid cable of the present invention is used in the same manner as known hybrid cables. Connect the cable to a power source, one or more data transmission sources such as computers, sensors, and finally to end devices such as computers, household appliances, industrial or entertainment equipment, etc. A suitable thickness of metal connected to the optical fiber enables any current transmission received by adjacent or nearby electrical conductors (or from any other source) to be transmitted along the fiber to the terminal device without interfering with the fiber's data transmission.

The present invention includes following scheme:

Option 1. Metallized optical fiber comprising:

A) optical fiber, and

B) a metal surrounding and in contact with the optical fiber, the metal having a thickness of at least 0.15 times the thickness of the optical fiber.

Aspect 2. The optical fiber of Aspect 1, wherein the metal comprises at least one of the following: copper, aluminum, a metal of the platinum group, or a metal of the noble metal group.

Aspect 3. The optical fiber of Aspect 1 or 2, wherein the metal coats the entire surface of the optical fiber.

Aspect 4. The optical fiber of Aspect 1 or 2, wherein the metal is clad to less than the entire surface of the optical fiber.

Item 5. The optical fiber of item 4, wherein said metal is in the form of a strip extending along the longitudinal axis of said fiber.

Item 6. The optical fiber of item 5, wherein said metal strip coats at least 10% of said optical fiber surface.

Option 7. Hybrid fiber/coaxial cable comprising:

A) coaxial cable, and

B) Metallized optical fiber comprising:

1) optical fiber; and

2) a metallic coating surrounding and in contact with the optical fiber,

The thickness of the metal coating is at least 0.15 times the thickness of the optical fiber.

Item 8. The hybrid fiber optic/coaxial cable of Item 7 connected to a power source.

Item 9. The hybrid fiber/coaxial cable of Item 7 or 8, wherein the metal is copper and the metal coats the entire surface of the optical fiber or substantially the entire surface of the optical fiber.

Embodiment 10. A method of transmitting a data signal via a cable, the method comprising connecting the cable to a power source and a data signal source, the cable comprising the hybrid fiber/coaxial cable of Embodiment 7.

It is specifically intended that the invention is not limited to the embodiments and illustrations contained herein, but that the invention includes variants of those embodiments including parts of the embodiments and elements of different embodiments that fall within the scope of the claims. combination.

Claims (10)

1. A metallized optical fiber comprising: A) optical fiber, and B) metal surrounding and in contact with the optical fiber, the metallized optical fiber is characterized in that the thickness of the metal is at least 1 times the thickness of the optical fiber. 2. The optical fiber of claim 1, wherein said metal comprises at least one of the following: copper, aluminum, a metal of the platinum group, or a metal of the noble metal group. 3. The optical fiber of claim 1 or 2, wherein said metal coats the entire surface of said optical fiber. 4. The optical fiber of claims 1 or 2, further characterized in that said metal cladding is less than the entire surface of said optical fiber. 5. The optical fiber of claim 4, wherein said metal is in the form of strips extending along the longitudinal axis of said fiber. 6. The optical fiber of claim 5, wherein said metal strip coats at least 10% but less than 100% of said optical fiber surface. 7. Hybrid fiber optic/coaxial cable comprising: A) coaxial cable, and B) Metallized optical fiber comprising: 1) optical fiber; and 2) A metal coating surrounding and in contact with the optical fiber, the metallized hybrid fiber/coaxial cable is characterized in that the thickness of the metal is at least 1 times the thickness of the optical fiber. 8. The hybrid fiber optic/coaxial cable of claim 7 connected to a power source. 9. The hybrid fiber/coaxial cable of claim 7 or 8, wherein said metal is copper, said metal coating the entire surface of said optical fiber or substantially the entire surface of said optical fiber. 10. A method of transmitting data signals over a cable, said method comprising connecting said cable to a source of power and data signals, said cable comprising the hybrid fiber optic/coaxial cable of claim 7.